The invention concerns a method of establishing a toll-free communication connection between a calling terminal and a called terminal, as well as a service unit and an exchange for establishing a toll-free communication connection.
Many telephone networks provide a service feature which enables the called subscriber to accept the cost of a call. In the U.S. this service feature is known as the 800 service, and in the German Telecom it is the 130 service. A description of this service feature can be found in the article xe2x80x9cCharacteristics of intelligent networksxe2x80x9d by L. Alvarez Mazo et al., Electrical Telecommunications, volume 63, no. 4, 1989, pages 314 to 319.
If a subscriber dials a toll-free call number, which for example begins with the digital sequence 130 in Germany and with the digital sequence 800 in the U.S, the connection request is routed to a control unit of the respective communications network. This control unit converts the called number into a xe2x80x9cnormalxe2x80x9d call number which represents the called subscriber""s actual call number. It further routes the charging of the fees in such a way, that the applicable fees for the connection are charged to the called subscriber. In that case the control unit has an IN (Intelligent Network) architecture.
This solution has the disadvantage that a toll-free call number is only available locally in a single communications network. It is therefore not possible to dial a toll-free universal call number which is valid in several national telephone networks and can thus be used for example in the U.S. and in Germany as well.
ITU-T""s recommendation E.152 xe2x80x9cInternational Freephone Servicexe2x80x9d of July 1996 describes further possibilities about how the above service feature can also be provided for a connection between subscribers of different national telephone networks. One possibility is to locate the control unit in the network of the calling subscriber, and to convert a toll-free local call number of this network into the international call number of the called subscriber. Another possibility is that a network enables dialing a toll-free local call number from outside of this network. However, both of these possibilities also have the disadvantage already mentioned above.
The invention now starts with another possibility described by this recommendation. This possibility is also described in greater detail in ITU-T""s recommendation E.169 xe2x80x9cNumbering Plan for Universal International Freephone Servicexe2x80x9d, February 1996. It provides a universal international toll-free phone number in the international numbering area. Such a call number includes a service code for a global service (digital sequence 00-800) and a universal subscriber number.
This solution makes it possible to dial a toll-free universal call number, which can be used in all national telephone networks. However there is the disadvantage that the issuance and the management of such call numbers must take place centrally all over the world, and the supply of available call numbers is limited, which is also why extensive preconditions exist for obtaining such a number.
The object of the invention is to enable the use of toll-free universal call numbers, which do not need to be centrally issued and managed all over the world.
This object is achieved with a method of establishing a toll-free communication connection between a calling terminal, which is connected to a first communications network, and a calling terminal, where with this method of establishing a connection the calling terminal sends a connection request with a toll-free universal call number as the called number to the first communications network, wherein the toll-free universal call number is provided by a service unit of a second communications network, that the connection request is recognized as a connection request with a toll-free universal call number, and an inquiry is sent by the first communications network to this service unit of the second communications network, that the service unit determines a toll-free local call number of the first communications network from the toll-free universal call number, and informs the first communications network of this, and that the first communications network establishes the requested connection in accordance with this determined toll-free local call number.
This object is also achieved by a service unit for establishing a toll-free communication connection between a calling terminal which is connected to a first communications network, and a calling terminal, wherein the service unit is located in a second communications network, that the service unit is equipped with a reception unit for receiving an inquiry from the first communications network which includes a toll-free universal call number, that the service unit is equipped with a control unit for determining a toll-free local call number of the first communications network from the toll-free universal call number, and that the service unit is equipped with a transmission unit for returning the determined toll-free local call number to the first communications network.
This object is still further achieved by an exchange of a first communications network with means to receive a connection request with a toll-free universal call number as the called number, wherein the exchange is equipped with means which are designed to recognize the connection request as one with a toll-free universal call number, and to send an inquiry to the service unit of a second communications network which provides this toll-free universal call number, and that the exchange is equipped with means for receiving a toll-free local call number returned by the service unit, and that the exchange is equipped with means for controlling the establishment of the requested connection via the first communications network in accordance with this toll-free local call number.
This object is also achieved by a first communications network with means for receiving a connection request with a toll-free universal call number as the called number, wherein the communications network is equipped with means designed to recognize the connection request as one with a toll-free universal call number, and send an inquiry to a service unit of a second communications network which provides this toll-free universal call number, that the communications network is equipped with means for receiving a toll-free local call number returned by the service unit, and that the communications network is equipped with means for controlling the establishment of the requested connection via the first communications network in accordance with this toll-free local call number.
The invention is based on the idea of providing a xe2x80x9cvirtualxe2x80x9d toll-free universal call number, which is issued and managed by a local provider, for example a national network operator or a service provider, and to map this toll-free universal call number by means of a service point of this network operator or service provider, respectively to a locally valid toll-free call number of that communications network to which the calling subscriber is presently connected. The result is a twofold conversion of such a toll-free universal call number: first the toll-free universal call number is converted into a respective toll-free local call number, and then into the target call number.
In the sense of the invention a toll-free connection and a toll-free call number must be understood in that the called subscriber takes over all or at least part of the fees charged for such a connection.
One advantage of the invention is that each network operator or service provider of a communications network is able to offer toll-free universal call numbers as an additional service. This increases the available call numbers, the management and the issuance of such numbers is decentralized and therefore becomes more flexible.
The invention can be integrated at low cost into existing mobile radio networks, if the subscriber profile recognizes the dialing of a xe2x80x9cvirtualxe2x80x9d toll-free call number. The invention can of course also be integrated into all other communications networks, particularly telephone networks.
Other advantages are obtained particularly if an identification of the calling subscriber or terminal is also taken into account in the conversion of the universal into the toll-free local call number. In this way a toll-free universal call number can be used multiple times for different groups of subscribers.